Combined oral contraceptive pill: counselling

A 19-year-old female starts Microgynon 30 (combined oral contraceptive pill) on day 8 of her cycle. How long will it take before it can be relied upon as a method of contraception?


2 days

5 days

7 days

Until first day of next period

Contraceptives - time until effective (if not first day period):
instant: IUD
2 days: POP
7 days: COC, injection, implant, IUS

Combined oral contraceptive pill: counselling

Women who are considering taking the combined oral contraceptive pill (COC) should be counselled in a number of areas:

Potential harms and benefits, including
the COC is > 99% effective if taken correctly
small risk of blood clots
very small risk of heart attacks and strokes
increased risk of breast cancer and cervical cancer

Advice on taking the pill, including
if the COC is started within the first 5 days of the cycle then there is no need for additional contraception. If it is started at any other point in the cycle then alternative contraception should be used (e.g. condoms) for the first 7 days
should be taken at the same time everyday
taken for 21 days then stopped for 7 days - similar uterine bleeding to menstruation
advice that intercourse during the pill-free period is only safe if the next pack is started on time

Discussion on situations here efficacy may be reduced*
if vomiting within 2 hours of taking COC pill
if taking liver enzyme inducing drugs

Other information
discussion on STIs

*Concurrent antibiotic use
for many years doctors in the UK have advised that the concurrent use of antibiotics may interfere with the enterohepatic circulation of oestrogen and thus make the combined oral contraceptive pill ineffective - ‘extra-precautions’ were advised for the duration of antibiotic treatment and for 7 days afterwards
no such precautions are taken in the US or the majority of mainland Europe
in 2011 the Faculty of Sexual & Reproductive Healthcare produced new guidelines abandoning this approach. The latest edition of the BNF has been updated in line with this guidance
precautions should still be taken with enzyme inducing antibiotics such as rifampicin